The tactile contact lens

This paper introduces a device for enhancing tactile perception of surface undulation. This device, which we call a "tactile contact lens," is composed of a sheet and numerous pins arranged on one side of the sheet. Our experimental results show that a small bump on a surface can be detected more accurately through this device than by bare finger and than through a flat sheet. A mathematical analysis of this phenomenon suggests two causes of this phenomenon. One cause is a lever-like behavior of the pins, which converts the local inclination of the object surface into the tangential displacement on the skin surface. The second cause is the spatial aliasing effect resulting from the discrete contact, by which the temporal change in the skin surface displacement is efficiently transduced into the temporal change in the skin tissue strain. The result of the analysis is discussed in relation to other sensitivity-enhancing materials, tactile sensing mechanisms, and tactile/haptic display devices.